This is a continuation of a program, initiated in 1956, for the production of uniform lots of anterior pituitary hormones, other than ACTH, for use in research. Bovine and ovine growth hormone, prolactin, thyroid- stimulating hormone, follicle-stimulating hormone and luteinizing hormone are regularly prepared, carefully assayed for both primary and contaminating activities, and distributed gratis to qualified investigators anywhere in the world. Smaller quantities of hormones from pig pituitaries have been prepared. Limited amounts of highly purified preparations of growth hormones and gonadotrophins are prepared and distributed as reference reagents for radioimmunoassay of animal hormones. Some special preparations from other species (e.g., dog; rabbit) are available in mg amounts on request. The laboratory is a major processor of human pituitaries, producing hGH, hFSH and hLH for the National Pituitary Agency. In addition, highly purified preparations of human pituitary hormones for use in radioimmunoassay are prepared and distributed gratis to investigators. The laboratory acts as a depot for a variety of special hormonal reagents. Details will be found in Endocrinology 94, 626, 1974. The program also involves continuing research into methods of preparation and assay of the pituitary hormones and into studies of their chemistry.